After Columbia: NASA ought to have clear and sensible purposes.

But I, remembering, pitied well

And loved them, who, with lonely light,

In empty infinite spaces dwell,

Disconsolate. For, all the night,

I heard the thin gnat-voices cry,

Star to faint star, across the sky.

Rupert Brooke was speaking of the stars themselves, as seen from a country lane in Cambridgeshire on a crisp fall evening 95 years ago. It is hard not to feel, though, that he had some premonition of there one day being real human voices squeaking disconsolately to one another, "star to faint star," across the lonely sky. At any rate, whenever I catch a TV news clip showing astronauts on board an orbiting shuttle, and hear their distorted voices, it is Brooke's lines that come to my mind.

Those news clips are few and far between nowadays. Other than as brief "filler" items in a slow news season, manned space travel is not interesting to the TV-watching public, except when something ghastly happens. The heroic days of the Apollo program are an entire generation behind us. In all likelihood, NASA prefers things this way. The nation's manned space effort is a quiet program, chugging away behind the scenes, doing . . . what? Best not to inquire.

I did inquire. To be precise, I went to the Internet and pulled off the NASA press kit for Shuttle Mission STS-107-the one that ended so horribly on February 1. Let us see. In the shuttle's payload bay we have: an experiment that will "examine bone formation . . . and bacterial and yeast cell responses to the stresses of spaceflight" . . . a German project to measure "the development of the gravity-sensing organs of fish in the absence of gravity" . . . the "Mediterranean Israeli Dust Experiment" . . . "the Critical Viscosity of Xenon-2" . . .

I do not doubt that these are very worthy experiments. But unfortunately, everything in this world must be paid for, and the price of carrying out these investigations aboard the shuttle is extraordinarily high-around $10,000 per pound of payload. Presumably the scientists looking into the critical viscosity of xenon-2 are happy to have their experiment aboard the shuttle. My guess, though, is that if they were told that no more shuttle flights were available, and that they would have to find some other way to spend their $10,000 per pound, they would not be inconsolable.

Contrariwise, there are many scientists whom the shuttle program makes very unhappy indeed. Take those involved with the Pluto-Kuiper Express mission, for instance. This was a proposal to send a small, unmanned spacecraft to fly by the planet Pluto, at the outermost edge of the solar system. Pluto is the only planet not yet visited by a spacecraft. Its importance lies in the fact that it is not, strictly speaking, a planet at all, but just the largest member of the Kuiper Belt, a zone of billions of icy objects left over from the solar system's formation. It is thought that these objects are occasionally dislodged from their orbits by tiny gravitational changes arising from their mutual interactions, and from the sun's passage among the stars. They then fall in to the inner solar system, adding to the chances of a civilization-destroying impact with our own planet. It would be nice to understand more about the Kuiper Belt, and about Pluto, which at present is known to us only as a fuzzy blob. Unfortunately, the PKE mission was canceled in September 2000 due to cost overruns. A scaled- down version has since been approved, with an absolute cost cap of $500 million, but it has been a long and hard-fought struggle.

By way of comparison, three years ago the General Accounting Office estimated the cost of a single shuttle launch at $512 million. The shuttle budget is a cuckoo in the nest of the space budget as a whole, grabbing all funds for itself from the limited amount Congress is willing to appropriate for non-military space flight. For less than the cost of putting seven people into orbit for two weeks and acquiring some incremental understanding of things like "yeast cell responses to the stresses of spaceflight," we could map Pluto and get a better fix on our odds for survival as a species.

These are the tradeoffs that space scientists are forced to engage in on account of the shuttle, and the political pressures to keep it flying. The situation has been made worse by the promotion of the International Space Station, a techno-diplomatic extravaganza of no practical value whose cost, name notwithstanding, falls mainly on the U.S. taxpayer.

As well as being expensive, the shuttle fleet is old. NASA should be spending much more than it does on planning a replacement. Over the past few years, Congress has in fact appropriated nearly $5 billion to such a replacement, but nothing has come of it. Everyone who knows the realities of the shuttle program-everyone, that is, other than the big aerospace contractors who milk it-is bitter and angry about these things. Here, for example, is spaceflight journalist Carlton Meyer, writing on the "Spacedaily" website late last year:

Perhaps NASA should build a "Sea Station" 1000 feet below the sea and use submarines to take foreigners and other salaried government tourists on "missions" to conduct "experiments" and set "endurance records" while "improving international relations." This idea may seem crazy, but it would be much cheaper than the shuttle program and accomplish just as much.

Meyer predicted another catastrophic accident, but this did not require any special foresight on his part. The design of the shuttle-1970s technology, compromised by chronic funding uncertainties and severe budget constraints, and overseen by government bureaucrats-virtually guarantees regular failures. The clamor to fix whatever it was that caused Columbia to disintegrate will at best have the result of reducing by one the hundreds of things that can go wrong on a shuttle flight. Ten launches later-or 20, or 50-another seven astronauts will be killed by some different malfunction.

The shuttle is, in fact, extraordinarily dangerous. Now, space flight will never be an anxiety-free enterprise. The only practicable way to get human beings into space is by dint of a colossal controlled explosion. Having once got them into space, their velocity relative to the surface of the earth being then at least 17,000 miles per hour, getting them back-reducing that velocity to zero-needs either an equivalent explosion (in which case the explosive must be taken aloft with them) or else the use of air resistance for braking. Only the latter is realistic, and it means subjecting the re-entry vehicle to extreme heat and stress at altitudes far beyond the reach of emergency help.

Barring some sensational discovery in fundamental physics-something equivalent to the gravity-shielding "Cavorite" that took H. G. Wells's astronauts aloft in The First Men in the Moon-we are stuck with these fiery realities of combustion and friction. There are good reasons to think, though, that the perils of manned space flight could be reduced by an order of magnitude. Just look at the record: The shuttle mission that ended in catastrophe on February 1 was the 113th. Of that 113, two ended in disaster, with the loss of all hands. This means that for an astronaut sitting in a shuttle waiting for ignition, his odds of being killed during the mission are, on present evidence (and there are people who will tell you we have been lucky), around 2 percent. Those are simply terrible odds. It is difficult to think of any human activity other than battlefield combat that is equally dangerous. The equivalent risk for an Air Force test pilot taking off is hundreds of times smaller. For a civilian starting up his car or boarding a plane, it is tens of thousands of times smaller. Forty years into the era of manned space flight, we can surely do much better than 2 percent.

For I do believe that manned space flight is worthwhile. Practical arguments aside, we ought to be taking slow, tentative, and sensibly funded steps into space. Those lines of Rupert Brooke's hint at an important feature of a manned space program: It is a romantic enterprise. It has an appeal to our deeper selves, most especially to those aspects of our consciousness that other national endeavors cannot reach-aspects concerned with our relationship to the larger cosmos, the future of our species, the fragility of our civilization, and the divine purpose in providing us with such inconceivably vast empty spaces to roam in, so innumerably many barren worlds of rock, ice, and frozen vapor to examine.

This romance is not a negligible consideration, not for Americans. For a coldly utilitarian people-the ancient Romans, say, or the modern Chinese-it might be. For us, as Calvin Coolidge noted a lifetime ago: "The things of the spirit come first." There is a respectable case to be made that, at this point in human development, there is no need for human beings to be in space at all. I doubt Americans can be persuaded by that case. Popular sentiment is in favor of a manned space program, and the nation ought to have one; but not, surely, one in which spiders and yeast cells are hoisted aloft at $500 million a throw, with 2 percent odds on fiery destruction. Let us do a little rethinking about what we want from manned space flight, and how best we can get it.